Soldiers are taught to be killers - it's part of their job - and their training includes firing at an image of the enemy. German photographer Herlinde Koelbl has made a study of these targets and spoken to many soldiers, but a century after the start of World War One, she still hopes for a world without conflict.

When we remember certain events, they are almost always connected to images. Images are the condensed emotions that don't allow us to forget. Which images of World War One do we carry in our minds?

Although it was a war of great historical importance whose conflicts have after-effects to the present day, personal stories were rarely told in families - in marked contrast to World War Two, which is deeply rooted in the German consciousness due to the Holocaust and the guilt. We remember photos from the start of the war, on which soldiers hasten to train stations, happy and laughing, to be part of it, still feeling like heroes. But that was to change.

At the end of the war, photos show dead soldiers in the trenches, sprawled out, crooked or lying mutilated in the mud. And we also see the pictures of men returning, of tired, emaciated or wounded bodies and numbed, empty faces. They were targets, and they survived. But 10 million soldiers and six million civilians were killed in that war.

In my project Targets I look at the present day. I visited 30 countries to document the appearance of the targets with which soldiers today are conditioned to shoot, or as one trainer said: "They are supposed to learn to hit, not shoot." Another said, "It sounds cruel, but you have to learn to kill automatically in order to function."

How is he represented today - the enemy that soldiers are later expected to kill? Is he an abstract figure? Does he have a face, and if so, what kind? Has the image of the enemy changed?

Image copyrightHerlinde KoelblImage caption
A target used in training in the US

Yes, it has changed. The person who accompanied me to an American shooting range explained: "My target used to be the green figure of Ivan with a red star on his helmet." The enemy was the Soviet Union. The red star has gone. New targets have appeared, figures with eastern-looking clothing and dark skin. A new enemy?

But who is the enemy? The enemy is always the other one. "I never felt guilty about killing people who deserved to die. In my eyes they deserve to die because they are the enemy. I am trained to think that way," a soldier told me.

Whichever side a soldier is on, in America, in China, in Russia or in Israel, he always believes he is on the right side. And he has to believe this in order to be willing to die. "I accepted killing and being killed. It's part of the job."

To want and to have to prove themselves in such extreme situations is an experience that they never forget. And that some of them seek again and again. "You are never more alive than when you are faced with death."

However it is not only the danger of death that stays in the memory - it is always also the question of whether they did the right thing. One soldier told me, "In Iraq a kid pointed a gun at us, and we shot him. Afterwards we noticed that the gun wasn't loaded. Then you ask yourself, 'Was it right what you were doing?' You try to suppress these thoughts, but they always come back."

Or the thoughts of an officer about his responsibility for comrades that he lost: "I should have tried to protect these guys. I should have been able to see this coming, I should have thought about this, planned for it. And that burden of guilt will last forever."

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Image copyrightJohannes Rodach

German artist and photographer Herlinde Koelbl is known for her large-scale, thematic projects such as Targets and Jewish Portraits

You can listen to The Essay on BBC Radio 3 on Friday 2 January at 22:45 GMT or afterwards on the BBC iPlayer - it was recorded in Dresden as part of a global year-long partnership between the British Council, BBC World Service and BBC Radio 3 called The War That Changed the World

Humans have natural inhibitions about killing, as Dave Grossman describes in his book, On Killing. According to Grossman, we have become good at training people to kill as a reflex and creating cold-blooded killers. The key to this is conditioning through desensitisation in training.

A brutal method of removing inhibitions was practised in World War One already, as shown by a photo from the US Army from 1917: killing with a bayonet.

A soldier of the Royal Fusiliers described it as follows: "This great big sack was hung up on a string and we had to assume that it was a person. You had to push it in, you were told how to twist it and pull it out again. That was the part of the training when you really began to think that you've got to beat a man in front of you."

Image copyrightALAMYImage caption
Soldiers at a US training base learn how to use a bayonet, 1917

The methods are perfected, increasingly directed to reducing inhibitions. This is one of the reasons why simulation systems are in use in many countries today, and the soldiers themselves are the targets.

The soldier, his weapon, the vehicles - as much as possible is electronically networked. This creates a pseudo-realistic situation - the soldiers shoot straight at their comrades, who are acting as "enemies". The aim is desensitisation with a view to future reality.

Bearers of horror and salvation, bearers of death and freedom. Armies are both of these

In Ukraine and Iraq we are now seeing once again how fragile peace is. We (in Western Europe) should be more aware of our good fortune in living in peace for more than half a century. Having taken photographs in so many crisis regions, I have the impression that, for us, peace is almost taken for granted.

The questions that I have asked myself in this work over a period of years became manifest in an exemplary way one autumn day. In the morning I had photographed young Canadian soldiers on a training ground in Germany, preparing for their tour of duty in Afghanistan. Sunshine, a good mood. It was their daily routine, just training.

A few hours later and a few kilometres away, I visited a military cemetery. Pensively I walked along the rows of gravestones. Many of the fallen did not die until shortly before the end of the war, in 1944 or 1945. Born in 1925, died in 1944, not even 20 years old. The war wiped out millions of lives.

The stillness was abruptly broken by the heavy, thudding sound of tanks shooting on one of the training grounds. Back to the present. Soldiers training for war. Now it is Afghanistan. Some other time it will be a different country. Why?

Late afternoon, next stop - the former concentration camp of Bergen-Belsen. Stillness again. An oppressive atmosphere in which the horror of those days was perceptible. The British army liberated the inmates and ended the atrocities.

The same question: why armies, why war? Bearers of horror and salvation, bearers of death and freedom. Armies are both of these.

Image copyrightGetty Images

The moral attitude of military officers, from the leader of a unit to a general, has acquired great, even decisive importance. This already begins in training, not in war.

Wise decision-makers are called for, whose actions are founded on ethical insights, who respect human life and the rule of law, who do not label opponents as "inhuman" and thus make targets of them.

I saw the same paper targets in different countries... ordered from the same catalogue

"As a leader you set an example, you don't let anything pass. You have to make the world as black and white as possible. Avoid grey, because it will get you into trouble. Atrocities are always a failure in leadership," an American colonel told me.

There are laws. But soldiers sense the unspoken grey and undefined areas in their leaders' minds. Then it is possible to cross boundaries without being punished.

War has changed. The new, usually asymmetrical war is no longer waged on battlefields but in villages and cities. That is why training grounds, proper ghost towns for practice, are springing up in many countries. Sometimes they are perfectly fitted out, as in America in Fort Irwin, where mosques with golden domes can be seen.

Image copyrightALAMYImage caption
A training exercise for US infantry at Fort Irwin, California, in 2007

In Israel too a complete ghost town has been built, a gigantic sea of houses. There are street signs or names of buildings such as The Bank of Palestine and El Baladia City Hall.

There was a great contrast in training between the countries that were technically highly advanced, and developing countries. The target in Afghanistan was just a foam mattress with a piece of paper pinned on to it. The freedom fighters or terrorists, depending on how you look at it, only had circles that they drew themselves on white paper. Sometimes I saw the same paper targets in different countries, as they had all been ordered from the same catalogue.

Image copyrightHerlinde KoelblImage caption
A target used for training in South Africa

In South Africa I made a surprising discovery. The targets there had the same motifs as in England. The same applied to Kenya, Uganda, and Australia. The British army made colonial history in the shape of training targets, and thus leaves its traces in these countries to this day.

One soldier on operations said, "There will always be war, as long as there is man." History supports his view. Since Cain and Abel, there have been violence and war in all cultures, for many reasons. "War is the chess game of politics and we are the figures," a soldier told me. The huge military cemeteries filled with those who fell in many wars demonstrate this to us with great clarity.

Is there hope for a better future without war? It is politicians who can contribute to this and aim to establish more justice in society worldwide, taking democracy as guidance to prevent intolerance, extremism and violence.

And it is political decision-makers who send soldiers to war. This is perhaps the most difficult decision that parliamentarians have to make, as by doing so they take responsibility for the lives of the soldiers and for what these soldiers do in carrying out their task. I hope they are always aware of this. Politicians must focus on avoiding war, on the effort of talking to the others and negotiating.

Political questions cannot be decided by war, as has been demonstrated not only in World War One. On the contrary, war often creates new and more difficult problems.